US EPA

5240991 

Journal Article 

Rate of Respiratory Excretion of Dimethylsulfide in Cats Given Dimethylsulfoxide 

Borgstedt, HH; Distefano, V 

1967 

1 

Toxicology and Applied Pharmacology
ISSN: 0041-008X
EISSN: 1096-0333 

10 

3 

Respiratory elimination of dimethyl-sulfide (75183) (DMS) following exposure to dimethyl-sulfoxide (67685) (DMSO) was studied in cats. Anesthetized spontaneously breathing or mechanically ventilated cats, some of which were hepatectomized, were injected intravenously with up to 400mg/kg DMSO. Elimination of DMS in the expired air was monitored for 5.5 hours. The respiratory rates of the spontaneously breathing cats were monitored. The respiratory rate in mechanically ventilated cats was alternated between 500 and 1000 milliliters (ml) per minute (min) at 15min intervals. DMS was detected in the expired air within a few seconds after DMSO injection. Data for a cat breathing spontaneously at 7 to 8 liters per 15min injected with 200mg/kg DMSO indicated that the instantaneous exhalation of DMS varied from 50 to 150 nanograms/ml. Cumulative excretion of DMS over the 5.5 hour period amounted to 20.4mg. In mechanically ventilated cats injected with 200mg/kg DMSO, elimination of DMS in the expired air was only half that of spontaneously breathing cats. The total amount of DMS exhaled per 15min interval was approximately constant at around 0.9mg/15min. Cumulative excretion of DMS increased with increasing DMSO dose. Overall elimination of DMS amounted to about 3% of the DMSO dose at each dose level. Cumulative excretion of DMS in hepatectomized cats did not differ significantly from that of intact cats. The authors conclude that cats administered DMSO intravenously exhale approximately 3% of the dose as DMSO over 5 hours. The rate of DMS exhalation appears to be limited by its rate of metabolic production and not by respiration related factors. The liver does not appear to be a major site for reducing DMSO to DMS.